The invention relates to a method of controlling the supply of fuel to an internal combustion engine during engine start-up and is especially applicable to cold-weather starting.
Fuel supply control systems for vehicular engines commonly employ different control methods for fuel supply during engine start-up and during normal operation. In such prior art fuel supply methods, the fuel injection or carburetion quantity starts rather high at the beginning of engine cranking and gradually decreases at a predetermined rate to a fuel supply quantity corresponding to idling. The high initial fuel quantity ensures an adequately rich air/fuel mixture for ignition, but the predetermined rate of decrease may be too fast to maintain adequate fuel concentration throughout the starting process, especially in very cold weather. That is, even if combustion occurs and the engine catches briefly, the fuel supply quantity may drop so quickly that the engine dies again. Furthermore, if the engine should achieve some combustion and then stop due to insufficient fuel, the resultant flooding of the spark plugs will delay the next attempt to start the engine.